Asthma is the most common chronic disease affecting children. It has been suggested that to gain a full picture of the impact of asthma on children, it is necessary to make direct measurements of quality of life (QOL) (Juniper et al., 1996). A valid conceptual model to measure QOL in children living with asthma would help providers learn about conditions that have the greatest impact on patients' lives and help evaluate the relative importance of different approaches to patient care (Wilson & Cleary, 1997). Juniper and colleagues (1996) developed a conceptual model to measure QOL of children living with asthma, the Pediatric Asthma Quality of Life Questionnaire (PAQLQ). This questionnaire was developed within an ethnically homogenous sample and then translated into over 20 languages including Spanish. The Principal Investigator intends on using the PAQLQ as an outcome measure for group comparisons, English-speaking versus Spanish-speaking children. However, little is know about the measurement invariance of the PAQLQ for between population group comparisons. Relatively new analytical techniques are available to evaluate instruments for measurement invariance which is a necessary requirement for appropriate between population group comparisons. Stewart and Napoles- Springer (2000) stated that a valid comparison of self-reported measures like the PAQLQ requires that the concepts have similar meaning across groups. Measures must conform to measurement invariance in similar ways across the groups being compared. Thus the purpose of the proposed research is, using secondary data, to examine the concepts and measurement properties of the English- and Spanish-language versions of the PAQLQ using SEM and measurement invariance analysis. Measurement invariance analysis involves testing the equivalence of measured constructs in two or more independent population groups to assure that the psychometric properties are similar in each group and therefore group comparisons are appropriate. The following are the aims for this application: Aim 1. Using the confirmatory approaches of SEM evaluate the construct validity of the PAQLQ in both the English- and Spanish-language versions. Aim 2. Evaluate the equivalence of the English- and Spanish-language versions of the PAQLQ using measurement invariance analysis. Aim 3 if measurement invariance is not achieved between the English- and Spanish-language versions of the PAQLQ, then several steps will be taken using SEM to refine the instrument to improve its construct validity, measurement equivalence across populations, and to minimize bias fro between group analyses. When using quality of life as an outcome to capture quality care, between diverse groups, it is vital that researchers and policy makers have confidence in the fidelity of the instrument. The Pediatric Asthma Quality of Life Questionnaire has not been tested for measurement invariance, a relatively new analytical technique, which is a necessary requirement for appropriate between group comparisons [unreadable] [unreadable] [unreadable] [unreadable] [unreadable] [unreadable]